With the spread of various electronic devices, such as a smart phone, a tablet PC, a portable multimedia player (PMP), a personal digital assistant (PDA), a laptop PC, and a wearable device, various wireless communication technologies used for the various electronic devices to perform communication have been developed.
Recently, as one of the next-generation mobile communication systems, standardization work for a long term evolution (LTE) system has considerably been done in 3rd generation partnership project (3GPP). The LTE system is a technology to implement high-speed packet based communication having a transmission speed of about 100 Mbps, and has currently been commercialized.
Further, research for device to device (D2D) communication has been under way as as an aspect of the LTE system standards. D2D communication refers generally to a communication scheme for enabling user terminals that support the LTE system to perform communication with each other without passing through a base station. That is, the D2D communication technology is a technology whereby a D2D radio link is configured between adjacent devices through a wireless mobile communication interface using a mobile communication frequency band, and data is directly transmitted and received between the devices through the D2D radio link without passing through the base station.